Multiple disc pressure responsive control device

Abstract

A pressure responsive control device having a pressure housing assembly defining a pressure chamber, an actuable controller fixed to the housing assembly and, a pressure transducer hermetically closing the pressure chamber. The transducer includes plural duplicate snap acting pressure responsive diaphragms, a diaphragm control plate hermetically bonded to the diaphragms and a support member hermetically joined between the control plate and the housing assembly. The diaphragms each are formed from thin sheets of spring metal and includes a central dome section having a surface finish less than 6 microinches A.A. on both sides. The diaphragms are nested together so that confronting faces of the dished sections are engaged when the diaphragms flex.

I claim: 
     
       1. A pressure responsive control device comprising: (a) a pressure housing assembly defining a pressure chamber;   (b) control means supported by said housing assembly comprising a control member actuatable between first and second control positions; and,   
     
     
       (c) a pressure transducer hermetically closing the pressure chamber and effective to actuate said control member, said pressure transducer comprising a plurality of snap acting pressure responsive diaphragms each defining a central dome section and a surrounding peripheral section, said diaphragms stacked together with their central sections nested, each central section defined by a thin sheet of metallic spring material having a surface finish less than 6 microinches A.A. on the confronting surfaces thereof. 
     
     
       2. The control device claimed in claim 1 wherein the surface finish of said central sections ranges between 1 and 4 microinches A.A. 
     
     
       3. The control device claimed in claim 1 wherein each diaphragm is formed from a thin sheet of spring metal and said diaphragms are hermetically joined together along said peripheral sections. 
     
     
       4. The control device of claim 3 wherein said diaphragms are duplicates. 
     
     
       5. The control device claimed in claim 3 wherein said diaphragms are formed from stainless steel and said control means comprises an electrical switch for closing and interrupting an electrical control circuit.